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Variable engine valve control system with pressure differenceRelated Patent Categories: Internal-combustion Engines, Poppet Valve Operating Mechanism, Hydraulic SystemVariable engine valve control system with pressure difference description/claimsThe Patent Description & Claims data below is from USPTO Patent Application 20070079780, Variable engine valve control system with pressure difference. Brief Patent Description - Full Patent Description - Patent Application Claims
FIELD OF THE INVENTION [0001] This invention involves a kind of internal combustion engine valve control system, particularly a kind of variable internal combustion engine valve control system with electric hydraulic control. BACKGROUND OF THE INVENTION [0002] The engine valve apparatus is an assembly of the engine valve mechanism. Since the operation of the internal combustion engine comprises four working processes of air intake, compression, doing work, exhaust, wherein the air intake and exhaust processes need to depend on the engine valve mechanism to convey combustible mixture exactly according to the working sequence of each cylinder (gasoline engine) or fresh air (diesel engine) and exhaust waste gas after burnt, the work described above is done by the valve of the valve mechanism thereby the valve apparatus plays a very important role in the operation of the engine, whereas the conventional valve mechanism is composed of cam shaft, valve rocker, valve spring, valve guide pipe, valve body and valve seat. It has been proved by practice that the valve mechanism of the structure described above operates inflexibly. When operating, valve timing (sequential control) and valve lift cannot change at any time according to working demand and therefore it cannot meet the requirements of high/low speed simultaneously. For this reason, a kind of variable valve control apparatus (VVA) is born at right moment, which can fall into three kinds of mechanical, electromechanical and hydraulic types according to the principle of their actuator apparatuses. In mechanical variable valve control system, the engine valve is still driven by cam system, only a phasemeter-cam joint is added in it. For instance, on the new Porsche 911 turbine engine, it can obtain variable timing and two setting/discrete lift controls by means of a fluid pressure driving cam phasemeter and it can be switched over through a fluid driving thrust switchgear. With the valve apparatus described above, variable timing and variable lift still cannot be independently controlled, the performance of the engine is still not ideal though it can economize fuel consumption, decrease waste gas displacement and obviously improve the performance of the engine. However, in the electromechanical VVA system, the initial actuator apparatus is an electromechanical one using a pair of electromagnets with springs, i.e. electromagnetic actuator apparatus. In laboratory experiment, it can economize fuel high up to 18% and decrease production of hydrocarbon, but in operating process it is found when the armature approaching the stop iron, the magnetic force rises very fast and it is difficult to improve controlling collision, consequently, its control reliability and firmness are worse and it cannot provide variable lift. Additionally, for increasing actuating force, it is necessary to add an additional battery besides the original battery of 12 V, but there are no more places for installing much more extra batteries in the present narrow space. There tend to increase the volume of the external housing for the purpose. Therefore, this kind of structure restricts extensive use of the electromechanical type variable valve control system. In hydraulic type variable valve control system, the initial actuator apparatus is a hydraulic actuator apparatus, for instance, US disclosure number US 2002/0184996A1 "Variable Lift Actuator" is such a plan. In this disclosure plan, it comprises valve, hydraulic supply equipment, pressure control regulator, hydraulic actuator apparatus and change valve. The said hydraulic actuator apparatus comprises hydraulic cylinder, actuating piston located in the cylinder with its upper and lower arranged coaxially, control piston and control spring. The actuating piston and the control piston divide the hydraulic cylinder into actuating chamber, control chamber and return fluid chamber. The actuating chamber is respectively connected to the hydraulic supply equipment or fluid tank through change valve. The control chamber is connected with hydraulic supply equipment through pressure control regulator. The return fluid chamber is connected with the fluid tank through return flow restrictor. One end of the piston rod is connected with the actuating piston. The other end of the piston rod is fixed on the valve head of the valve. The control piston can move axially with the piston rod. The control spring is situated in the return fluid chamber. Both ends of the spring are respectively supported between the lower end of the actuating piston and hydraulic cylinder bottom inner wall. When operating, a certain electric signal is given to the change valve and pressure control regulator so as to make change valve energized or disenergized, the pressure control regulator regulates the pressure inside the control chamber, finally makes the actuating chamber connected with the hydraulic supply equipment or the fluid tank and push the actuating piston to move up and down as required thereby attain the object of controlling the valve lift and timing. However, the patent described above has not been applied yet, it is analyzed after researched: (1) Along with the development of technology, the speed of automobile engines are more and more faster, completing four operating processes only needs 0.005 seconds, so, the response time of the change valve requires very fast. In order to meet the requirement of such a short response time, the cost of making change valve will be very high and finally leading to the products very expensive thereof no industrialized production can be carried out; (2) Because of the hydraulic cylinder embracing a control piston, a control chamber and control spring, the electrichydraulic pressure regulator, etc are positioned in the hydraulic circuit to make its system relative complicated and its reliability poor; (3) The opening height of the valve is related to the pressure of the hydraulic system, therefore, it is subjected to more interference from the system with shortcomings of large pulsation, etc.; (4) Simultaneously, as affected by hydraulic cylinder body, the performance of the control spring is subjected to a certain restriction so as to cause its frequency response not high. SUMMARY OF THE INVENTION [0003] The technical problem to be solved by this invention is aimed at present technological situation for providing a kind of variable engine valve control system with pressure difference, which is simple in structure, lower in cost and fast in response speed. [0004] The technical plan utilized in this invention for solving the technical problem described above is as follows: The variable engine valve control system with pressure difference comprises hydraulic supply equipment, hydraulic actuator apparatus, valve and spring controlling piston balance. The said hydraulic actuator apparatus comprises hydraulic cylinder, piston and piston rod. The said piston rod is coupled and moved with the valve. It is characterized by that the said piston described above divides the hydraulic cylinder into upper chamber and lower chamber, the said hydraulic supply equipment is connected with the upper chamber of the said hydraulic cylinder through fluid inlet pipe, and the lower chamber of the said hydraulic cylinder is connected with the said hydraulic supply equipment through pressure difference proportional reduce valve. [0005] The said pressure difference proportional reduce valve can be a pressure difference feedback control spool valve which includes valve body, spool valve core, proportional electromagnet, as well as fluid inlet port A, fluid outlet port B and fluid drain port T located on the valve body. The said valve body is equipped with a horizontally arranged transverse passage coupled with the said spool valve core. On the said spool valve core is installed a column boss which can move with the spool valve core thereby close or open the control fluid port through which the column boss is connected with the fluid drain port T. One end of the said spool valve core is concentrically contact with the crown bar of said proportional electromagnet. The other end of said spool valve core is supported to the spring. On the left side of said valve body there is a left-side passage connected with the upper chamber of said hydraulic cylinder and said hydraulic supply equipment through fluid inlet port A. On the central position of the valve body there is a longitudinal passage connected with said transverse passage and the lower chamber of said hydraulic cylinder through fluid outlet port B. There is a damping passage with damper between said left side passage and said longitudinal passage. The upper end of said longitudinal passage is connected with the left end of the right upper side passage of said valve body. The right end of said right upper side passage is connected with the right end passage of said valve body. The right lower side of said valve body is placed a right lower side passage with its one end connected with the return-flow port T and the other end connected with said transverse passage. [0006] The damper in said damping passage can be either a damping aperture or variable damper. The variable damper is formed from the second throttle side between said column boss and valve body. Meanwhile, for increasing working pressure difference, thinner bars projecting out of the valve body with sealing can be situated at the both ends of the spool valve core described above. The crown bar of said proportional electromagnet is supported to the slender bar at its relative end. [0007] A hydraulic--control check valve in parallel with said pressure difference proportional relief valve can be mounted between the upper chamber and the lower chamber of said hydraulic cylinder to make hydraulic fluid flow into the lower chamber of the hydraulic cylinder from the upper chamber of the hydraulic cylinder so as to quicken the return speed of the valve head. [0008] It is better to place a protrusion on the top of said piston, correspondingly, a buffering (damping) chamber is coupled with the protrusion on the top cover of said hydraulic cylinder, and a fluid passage is situated in the hydraulic cylinder with its one end connected with the buffering (damping) chamber and its other end connected with the hydraulic supply equipment through the first check valve. [0009] A pressure accumulator can be installed on said general fluid inlet pipe. [0010] On said piston end surface opposed to the piston rod an auxiliary piston rod can be fitted coaxially with the piston rod projecting out of the hydraulic cylinder. The said spring can be sleeved either round the auxiliary piston rod described above or round the piston rod outside of the hydraulic cylinder. [0011] The another technical plan utilized in this invention for solving the technical problem described above is as follows: The variable engine valve control system with pressure difference comprises hydraulic supply equipment, hydraulic actuator apparatus, valve and spring controlling piston balance. The said hydraulic actuator apparatus comprises hydraulic cylinder, piston and piston rod. The said piston rod is coupled and moved with the valve. It is characterized by that the said piston divides the hydraulic cylinder into upper chamber and lower chamber. The said upper chamber and lower chamber are respectively connected with the first fluid port and the second fluid port existing pressure difference of a pressure difference proportional relief valve through the fluid inlet pipe and fluid outlet pipe. The said hydraulic supply equipment is connected with the fluid inlet port of the pressure difference proportional relief valve through the general fluid inlet pipe. [0012] The said pressure difference proportional relief valve can be a pressure difference feedback cone valve, which includes cone valve body, cone valve core, proportional electromagnet, the above mentioned fluid inlet port, the first fluid port and the second fluid port positioned on the cone valve body. The said cone valve core head is equipped with a canoed coupled with the rear end port of the cone valve body bore and its tail is supported to the crown bar of said proportional electromagnet, and a soft spring is sleeved round the said cone valve core with its one end supported to the cone valve body, its other end supported to said canoed end surface. The said fluid inlet port and the first fluid port are respectively connected with the front and rear end ports of the cone valve body bore. Between the second fluid port and the first fluid port there is a passage with a damping aperture. The second fluid port yet is connected with the fluid tank. [0013] As compared to the present technology, this invention has advantageous in: since utilizing pressure difference proportional relief valve as key control element, the height of the valve opening is not related to the pressure of the system, which is only depended on the pressure difference between the upper and the lower chambers of the hydraulic cylinder, therefore it does not need to use the displacement transducer to perform closed loop control, it only needs to change electric signal to change the pressure difference of the upper and lower chambers of the hydraulic cylinder thereby attain the object of making variable valve lift and timing at any time as required, therefore the pressure difference proportional relief valve can be used instead of the change valve so as to make the system response speed fast, control simple, cost low, reliability fine. With short operating fluid passage the system is less interfered because the operating mode of the pressure difference proportional relief valve is normally opened without dead area, which can be directly mounted at the side of the cylinder. Furthermore, a hydraulic control check valve situated between the upper and lower chambers of the hydraulic cylinder causes the return stroke of the piston faster to increase its response speed. The control spring is fitted outside of the hydraulic cylinder to make the performance of the spring no longer restricted by the volume of the hydraulic cylinder, which is more helpful for increasing the response speed of the system. Therefore, this invention can meet the requirement of higher operating speed of combustion engines. It can be popularized and applied on combustion engines. BRIEF DESCRIPTION OF THE DRAWINGS [0014] FIG. 1 is a diagrammatic view illustrating the system of embodiment 1 of this invention; [0015] FIG. 2 is a diagrammatic view illustrating the structure of the control spool valve 2a of FIG. 1; [0016] FIG. 3 is a diagrammatic view illustrating the part system of spool valve 2b of embodiment 2of this invention; [0017] FIG. 4 is a diagrammatic view illustrating the structure of pressure difference feedback spool valve 2c of embodiment 3 of this invention; [0018] FIG. 5 is a diagrammatic view illustrating the structure of pressure difference feedback cone valve 2d used in embodiment 4 of this invention; [0019] FIG. 6 is a diagrammatic view illustrating the system after having used pressure difference feedback cone valve 2d. DETAIL DESCRIPTION OF THE INVENTION Continue reading about Variable engine valve control system with pressure difference... 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